In a typical ink jet recording or printing system, ink droplets are ejected from a nozzle at high speed towards a recording element or medium to produce an image on the medium. The ink droplets, or recording liquid, generally comprise a recording agent, such as a dye or pigment, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water and an organic material such as a monohydric alcohol, a polyhydric alcohol or mixtures thereof.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-receiving layer, and includes those intended for reflection viewing, which have an opaque support, and those intended for viewing by transmitted light, which have a transparent support.
An important characteristic of ink jet recording elements is their need to dry quickly after printing. To this end, porous recording elements have been developed which provide nearly instantaneous drying as long as they have sufficient thickness and pore volume to effectively contain the liquid ink. For example, a porous recording element can be manufactured by cast coating, in which a particulate-containing coating is applied to a support and is dried in contact with a polished smooth surface.
When a porous recording element is manufactured, it is difficult to co-optimize the image-receiving layer surface appearance and ink drying times. Good image-receiving layer surface appearance is obtained when it is virtually crack-free. A crack-free surface appearance can be obtained merely by adding more binder to the image-receiving layer. However, adding more binder increases dry time since the binder fills the pores in the image-receiving layer. Therefore, it is difficult to obtain an image-receiving layer which has a crack-free surface yet is fast-drying.
Another problem encountered with a recording element is ink coalescence which occurs when adjacent ink dots coalesce which leads to nonuniform density.
U.S. Pat. No. 6,037,050 and EP 888,904 relate to an inkjet recording element wherein an ink absorption layer comprises inorganic particles such as silica and a poly(vinyl alcohol) binder that is crosslinked with a hardener. However, there is no disclosure in these references that the crosslinker should be present in an amount greater than 10%, based on the binder.
It is an object of this invention to provide a porous ink jet recording element that exhibits good overall appearance without cracking and has an excellent dry time and reduced ink coalescence.